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Article
August 1978

Internuclear Ophthalmoplegia: II. Pursuit, Optokinetic Nystagmus, and Vestibulo-Ocular Reflex

Author Affiliations

From the Department of Neurology, Reed Neurological Research Center (Dr Baloh); Department of Ophthalmology, Jules Stein Eye Institute (Dr Yee); and Division of Head and Neck Surgery (Dr Honrubia); UCLA School of Medicine, Los Angeles.

Arch Neurol. 1978;35(8):490-493. doi:10.1001/archneur.1978.00500320010003
Abstract

• Smooth pursuit, optokinetic nystagmus (OKN) and the vestibulo-ocular reflex (VOR) were studied in four patients with internuclear ophthalmoplegia (two with bilateral and two with unilateral lesions). Horizontal smooth pursuit by an adducting eye on the side of a medial longitudinal fasciculus (MLF) lesion was normal in three of four patients; vertical pursuit was abnormal in all four. The horizontal VOR gain of slow components made by an adducting eye on the side of an MLF lesion was normal in all four patients. The vertical VOR gain was decreased in the two patients tested.

It is concluded that either there are pathways independent of the MLF for horizontal pursuit and vestibular signals that are not available to vertical signals, or vertical pursuit and vestibular eye movements require a higher rate of oculomotor neuron firing than equal-velocity horizontal eye movements.

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